Organic light-emitting diode display apparatus and method of manufacturing the same

ABSTRACT

Provided are an organic light-emitting diode (OLED) display apparatus and a method of manufacturing the OLED display apparatus. Pixel-defining layers (PDLs) are formed of inorganic and organic insulating layers to minimize non-uniformities of the thicknesses of organic emission layers (OEMLs) and planarize lower thin film transistors (TFTs). Therefore, a lifespan of the OLED display apparatus is improved.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2010-0005745, filed on Jan. 21, 2010, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present embodiments relate to an organic light-emitting diode (OLED)display apparatus and a method of manufacturing the same, and moreparticularly, to an OLED display apparatus including pixels havinguniform thicknesses and a method of manufacturing the same.

2. Description of the Related Art

An organic light-emitting diode (OLED) display apparatus is classifiedas passive matrix (PM) and active matrix (AM) type OLED displayapparatuses according to its driving method. In the PM type OLED(PM-OLED) display apparatus, anodes and cathodes are arrayed in aplurality of columns and a plurality of rows. Thus, the cathodes aresupplied with scanning signals from a row driving circuit. Here, onlyone of the plurality of rows is selected. Also, a data signal is inputinto each pixel from a column driving circuit. The AM type OLED(AM-OLED) display apparatus controls a signal input into each pixelusing a thin film transistor (TFT) and is appropriate for processing alarge number of signals. Thus, the AM-OLED display apparatus is mainlyused as a display apparatus for realizing a moving picture.

A passivation layer is formed on the TFT of the AM-OLED displayapparatus to passivate the TFT and as a planarizing layer forplanarizing an upper surface of the TFT. Pixel-defining layers (PDLs)are formed on the passivation layer.

If the PDLs are formed thick to prevent color mixtures among pixels, thethicknesses of emission parts formed among the PDLs vary. If thin PDLsare formed to solve these color mixtures, an upper surface of TFT areaunderneath the thin PDLs is not planarized. The present embodimentsovercome the above problems as well as provide additional advantages.

SUMMARY OF THE INVENTION

The present embodiments provide an organic light-emitting diode (OLED)display apparatus in which a thickness of an emission area is uniformand an upper surface of thin film transistor (TFT) area is planarizedand a method, of manufacturing the OLED display apparatus

According to an aspect of the present embodiments, there is provided anorganic light-emitting diode (OLED) display apparatus including: thinfilm transistor (TFT) which is formed on a substrate; first electrodewhich is formed on a planarizing layer in each pixel, wherein theplanarizing layer covers the TFT; pixel-defining layers (PDLs) whichincludes first PDL covering an end of the first electrode and second PDLexposing an end of the first PDL and covering the first PDL;intermediate layer which is formed on the first electrode and includesan emission layer (EML); and second electrode which is positionedopposite to the first electrode.

According to another aspect of the present embodiments, there isprovided a method of manufacturing an organic light-emitting diode(OLED) display apparatus, including: forming over a substrate firstelectrodes in each pixel; forming first PDLs covering ends of the firstelectrodes; forming second PDLs exposing ends of the first PDLs andcovering the first PDLs; and forming intermediate layers including EMLson the first electrodes; and forming second electrodes opposite to thefirst electrodes.

The second PDL may be formed on the first PDL to bury uneven partsformed on a planarizing layer.

The first PDLs may be formed of inorganic layers. The first PDLs may beformed of at least one of SiO₂, SiNx, Al₂O₃, CuOx, Tb₄O₇, Y₂O₃, Nb₂O₅,and Pr₂O₃ for example.

Each of the first PDLs may be formed to a thickness of from about 0.1 μmto about 1 μm.

The second PDLs may include organic layers. The second PDLs may beformed of one selected from the group consisting of polyacryl,polyimide, polyimide (PA), benzocyclobutene (BCB), and phenolic resin.

Each of the second PDLs may have a thickness from about 0.1 μm to about2 μm in a direction in which different color pixels are arrayed, and athickness between 0.1 μm and 1 μm in a direction in which equal colorpixels are arrayed.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present embodimentswill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is a schematic plan view of a pixel electrode part of an organiclight-emitting diode (OLED) display apparatus according to anembodiment;

FIG. 2 is an enlarged plan view of a pixel of OLED display apparatus ofFIG. 1;

FIG. 3 is a schematic cross-sectional view of an OLED display apparatusaccording to another embodiment; and

FIGS. 4 through 6 are schematic cross-sectional views illustrating amethod of manufacturing an OLED display apparatus, according to anembodiment.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary embodiments will now be described with reference to theaccompanying drawings. In the drawings, like reference numerals denotelike elements. These embodiments may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure is thorough, and will fully convey the scope of theembodiments to those skilled in the art.

In the drawings, the size and relative sizes of layers and regions maybe exaggerated for clarity. It will be understood that, unless otherwisespecified, when an element such as a layer, film, region or substrate isreferred to as being “on” another element, it can be directly on theother element or intervening elements may also be present.

FIG. 1 is a schematic plan view of a pixel electrode part of an organiclight-emitting diode (OLED) display apparatus according to anembodiment. FIG. 2 is an enlarged plan view of a pixel of the OLEDdisplay apparatus of FIG. 1.

Referring to FIGS. 1 and 2, the OLED display apparatus includes adisplay area in which red (R), green (G), and blue (B) pixels arerepeatedly arrayed. In the present embodiment, the R, G, and B pixelsare repeatedly arrayed in stripe patterns in columns and rows but thepresent embodiments are not limited thereto. For example, the R, G, andB pixels may be arrayed in zigzag patterns in which pixels in each roware misaligned, matrix patterns, or the like. In the present embodiment,a part of the display area is illustrated for convenience, the R, G, andB pixels are repeatedly arrayed in direction A-A′, and the same colorpixels are repeatedly arrayed in direction B-B′.

Each of the R, G, and B pixels includes a selective driving circuit,which has thin film transistors (TFTs) 30 and 40, a capacitor 50, andthe like, and an OLED 60. Each of the R, G, and B pixels includes a dataline 72, a gate line 71, and a power source line 73 that is a drivingpower source of the OLED 60.

The TFTs 30 and 40 respectively are a switching TFT and a driving TFT(hereinafter the TFTs 30 and 40 will be respectively referred to as theswitching TFT 30 and the driving TFT 40). The switching TFT 30 is drivenby a scan signal applied to the gate line 71 to transmit a data signalapplied to the data line 72. The driving TFT 40 determines an amount ofcurrent flowing into the OLED 60 according to the data signaltransmitted through the switching TFT 30.e.g., a voltage differencebetween a gate and a source. The capacitor 50 stores the data signaltransmitted through the switching TFT 30 for a frame.

A source electrode 31 of the switching TFT 30 is connected to theselective driving circuit through the data line 72, and a gate electrode32 of the switching TFT 30 is connected to another driving circuit (notshown) through the gate line 71. A drain electrode 33 of the switchingTFT 30 is connected to a first capacitor electrode 51 of the capacitor50 and a gate electrode 43 of the driving TFT 40.

A second capacitor electrode 52 of the capacitor 50 and a sourceelectrode 47 of the driving TFT 40 are connected to the power sourceline 73, and a drain electrode 45 of the driving TFT 40 is connected toa first electrode 61 of the OLED 60.

The number of TFTs and capacitors of the selective driving circuit isnot limited thereto, and the selective driving circuit may include alarger number of TFTs and a larger number of capacitors.

The OLED 60 includes the first electrode 61, which is a pixel electrode,and a second electrode (not shown) which is a common electrode andopposite to the first electrode at a predetermined gap from the firstelectrode 61. An intermediate layer (not shown) including an organicemission layer (OEML) intervenes between the first electrode 61 and thesecond electrode to emit light by the first electrode 61 and the secondelectrode.

A pixel-defining layer (PDL) 81 is formed around an end of the firstelectrode 61 of the OLED 60. The PDL 81 includes a first PDL 81 a, whichis an inorganic layer, and a second PDL 81 b, which is an organic layer.The first PDL 81 a is formed to cover the end of the first electrode 61,and the second PDL 81 b is formed on the first PDL 81 a to expose an endof the first PDL 81 a.

FIG. 3 is a schematic cross-sectional view of an OLED display apparatusaccording to another embodiment.

Referring to FIG. 3, the OLED display apparatus includes a plurality ofTFTs 40 and a plurality of OLEDs 60 which are formed on a substrate 10.

Each TFT 40 includes active layer 41, gate electrode 43, and source anddrain electrodes 45 and 47. A gate insulating layer 13 intervenesbetween the gate electrode 43 and the active layer 41 to insulate thegate electrode 43 from the active layer 41. The active layer 41 includessource and drain regions and a channel region. Here, a high-densitydopant has been injected into both ends of each of the source and drainregions, and the channel region is formed between the source and drainregions. The source and drain regions are respectively connected to thesource/drain electrodes 45 and 47.

Each OLED 60 includes a first electrode 61, a second electrode 65, andan intermediate layer 63 intervening between the first and secondelectrodes 61 and 65. The first electrode 61 is formed on a passivationlayer 17 in each pixel and connected to one of the source/drainelectrodes 45 and 47 of the TFTs 40 through via holes H1.

PDLs 81 are formed around ends of the first electrodes 61 to define thepixels. The PDLs 81 include first PDLs 81 a and second PDLs 81 b. Eachof the first PDLs 81 a is formed of an inorganic layer. The first PDLs81 a are formed between adjacent two first electrodes 61 and cover theends of the first electrodes 61. Each of the second PDLs 81 b is formedof organic layer on the first PDL 81 a to cover steep slope region P inwhich the end of the first electrode 61 and the via hole H1 is formed.The edge of second PDL 81 b is positioned at predetermined distance fromedge of the first PDL 81 a. Distances between edges of the first andsecond PDLs 81 a and 81 b may be about 1 μm or less and may bedetermined in consideration of aperture ratio and emission effectiveregion of the first electrode 61.

Thicknesses of the first PDLs 81 a may be each set to from about 0.1 μmto about 1 μm.

Thicknesses of the second PDL 81 b may be each set to from about 0.1 μmto about 2 μm in the direction A-A′ of FIG. 1 to prevent color mixturesamong adjacent R, G, and B pixels. And thickness of the second PDL 81 bmay be set to from about 0.1 μm to about 1 μm in the direction B-B′ ofFIG. 1 to minimize step differences of the OEMLs.

The first PDLs 81 a are formed of an inorganic material having similarsurface energy to that of the intermediate layers 63 stacked on thefirst electrodes 61. The second PDLs 81 b are formed of an organicmaterial having different surface energy from that of the intermediatelayers 63.

PDL is formed, and surface of the PDL is processed using a liquidrepellent to prevent color mixtures among pixels in order to form OEMLusing an ink jet or nozzle printing method. Here, if the PDLs is formedthick, thicknesses of the center of a pixel and the end of the pixelmeeting the PDL are different from each other. If the PDL is formedthin, surface curves of lower TFT area formed by uneven parts such assteep slope regions P or cracks A are not sufficiently planarized,wherein a via hole is formed in the steep slope region P, and the cracksA are formed in an etching process. Thus, moisture, oxygen, or the likepenetrates into the PDL, and shorts may occur between the first andsecond electrodes 61 and 65.

Accordingly, in the present embodiment, the first PDLs 81 a having thinthicknesses are formed around the end of the first electrode 61, and thesecond PDL 81 b is formed at predetermined distance from the edge of thefirst PDL 81. Thus, non-uniformities of the thicknesses of the OEMLs areminimized. Also, the second PDLs 81 b are formed on the first PDLs 81 ain which uneven parts such as cracks or the like are formed, to improvestep coverage in order to planarize lower TFT area and minimize shortbetween the first and second electrodes 61 and 65.

In the present embodiment, the second PDLs 81 b are formed on the firstPDLs 81 a, except on the ends of the first PDLs 81 a. According toanother embodiment, the second PDLs 81 b may be additionally formed inthe uneven parts such as the steep slope regions P or the cracks A.

Three TFTs and three capacitors are shown in FIG. 3 but the presentembodiment is not limited thereto. Thus, at least one TFT and at leastone capacitor may be formed.

FIGS. 4 through 6 are schematic cross-sectional views illustrating amethod of manufacturing an OLED display apparatus, according to anembodiment. The present embodiment exemplifies an OLED display apparatushaving a stripe structure in which the same color pixels are arrayed incolumn directions, and R, G, and B pixels are repeatedly arrayed in rowdirections from left to right.

Referring to FIG. 4, TFTs 40 and first electrodes 61 are formed above asubstrate 10.

The substrate 10 may be formed of a transparent glass material includingSiO₂ as a main component but is not limited thereto. That is, thesubstrate 10 may be formed of a transparent plastic material, a metallicmaterial, or the like.

If the OLED display apparatus is a bottom-emission type displayapparatus which realizes an image toward the substrate 10, the substrate10 is formed of a transparent material. If the OLED display apparatus isa top-emission type display apparatus which realizes an image in anopposite direction to the substrate 10, the substrate 10 does not needto be formed of a transparent material. In this case, the substrate 10may be formed of metal. If the substrate 10 is formed of the metal, thesubstrate 10 may include at least one or more selected from the groupconsisting of carbon (C), iron (Fe), chrome (Cr), manganese (Mn), nickel(Ni), titanium (Ti), molybdenum (Mo), stainless steel (SUS), an invaralloy, an inconel alloy, and a kovar alloy. However, the substrate 10 isnot limited thereto and may be formed of a metal foil.

An insulating layer 11 is formed on an upper surface of the substrate 10to prevent diffusion of dopant ions and penetration of moisture or airand function and for planarizing the upper surface of the substrate 10as a barrier layer and/or a buffer layer. The insulating layer 11 may beformed of SiO₂ and/or silicon nitride (SiNx) using a plasma enhancedchemical vapor deposition (PECVD) method, an atmospheric pressure CVD(APCVD) method, a low pressure CVD (LPCVD) method, or the like.

Active layers 41 of the TFTs 40 are formed on the insulating layer 11.In order to form the active layers 41 of the TFTs 40, amorphous siliconmay be deposited and crystallized on the insulating layer 11 to form apolycrystalline silicon layer (not shown), and the polycrystallinesilicon layer may be patterned.

Each active layer 41 of the TFTs 40 includes source and/or drain regionsand channel region. Each active layer 41 has the source and drainregions at ends of the active layer 41 corresponding to sides of gateelectrode 43 by doped with N-type or p-type dopants. The channel regionis formed between the source and drain regions.

A gate insulating layer 13 is formed on the active layers 41 of the TFTs40. The gate insulating layer 13 may be formed of an inorganic materialsuch as SiNx or silicon oxide (SiOx) using a PECVD method, an APCVDmethod, an LPCVD method, or the like.

The gate electrodes 43 are formed partially on the gate insulating layer13, and an interlayer insulating layer 15 is formed to cover the gateelectrodes 43.

The gate electrodes 43 may be formed of various types of conductivematerials such as Al, Mo, tungsten (W), Cr, Ni, or a compound of Al, Mo,W, Cr, and Ni. If light is to pass through the active layers 41 of theTFTs 40 and other elements, the gate electrodes 43 may be formed ofvarious types of transparent conductive materials such as ITO, IZO, orthe like.

Source/drain electrodes 45 and 47 are formed on the interlayerinsulating layer 15 and connected to the active layers 41 throughcontact holes formed in the interlayer insulating layer 15. Aplanarizing layer 17 is formed on the source/drain electrodes 45 and 47.

The planarizing layer 17 may be an inorganic insulating layer and/or anorganic insulating layer. The inorganic insulating layer may includeSiO₂, SiNx, SiON, Al₂O₃, TiO₂, Ta₂O₅, HfO₂, ZrO₂, BST, PZT, or the like.The organic insulating layer may include commercial polymer such aspolymethyl methacrylate (PMMA), polystyrene (PS), or the like, polymericderivative having a phenol group, acryl-based polymer, imide-basedpolymer, allylether-based polymer, amide-based polymer, fluorine-basedpolymer, p-xylene-based polymer, vinyl alcohol-based polymer, or a blendof commercial polymer, polymeric derivative, acryl-based polymer,imide-based polymer, allylether-based polymer, amide-based polymer,fluorine-based polymer, p-xylene-based polymer, and vinyl alcohol-basedpolymer. The planarizing layer 17 may have a complex stack structure ofan inorganic insulating layer and an organic insulating layer.

Stack structures of TFTs as described above are not limited thereto, andTFTs having various types of structures may be used. The presentembodiment exemplifies top gate type TFTs, but different types of TFTsmay be formed.

The first electrodes 61 are formed on the planarizing layer 17 as pixelelectrodes of an OLED and are electrically connected to one of thesource/drain electrodes 45 and 47 through via holes H1. The via holes H1are formed by etching the planarizing layer 17 and exposing thesource/drain electrodes 45 and 47.

The first electrodes 61 may be formed of various types of conductivematerials in each pixel. If the OLED display apparatus is abottom-emission type display apparatus which realizes an image towardthe substrate 10, the first electrodes 61 may be transparent electrodesand may be formed of ITO, IZO, ZnO, or In₂O₃ for example, having a highwork function. If the OLED display apparatus is a top-emission typedisplay apparatus which realizes an image in an opposite direction tothe substrate 10, the first electrodes 61 may be reflective electrodes.A reflective layer may be formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir,Cr, Li, Ca, or a compound of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li,and Ca, and ITO, IZO, ZnO, or In₂O₃, for example, having a high workfunction may be formed on the reflective layer in order to form thefirst electrodes 61.

Referring to FIG. 5, first PDLs 81 a are formed to cover ends of thefirst electrodes 61.

In order to form the first PDLs 81 a, an inorganic insulating layer isdeposited on a whole surface of the substrate 10 above which the firstelectrodes 61 have been formed, and patterned using a photolithographicprocess, to form openings H2 which expose central parts of the firstelectrodes 61.

The inorganic insulating layer may be formed of one or more inorganicinsulating materials selected from SiO2, SiNx, Al2O3, CuOx, Tb4O7, Y2O3,Nb2O5, Pr2O3, and the like using a sputtering method, a CVD method, adeposition method, or the like.

The first PDLs 81 a may be each formed to a thickness between about 0.1μm and 1 μm to minimize differences in thicknesses of OEMLs between endsand central parts of the first electrodes 61.

Referring to FIG. 6, second PDLs 81 b are formed on the first PDLs 81 a.

An organic insulating layer is deposited on the whole surface of thesubstrate 10 above which the first PDLs 81 a have been formed, and thenpatterned using a photolithographic process, to form openings H3 so asto expose central parts of the first electrode 61 and ends of the firstPDLs 81 a.

The organic insulating layer may be formed of one or more organicinsulating materials selected from the group consisting of polyimide,polyamide, acrylic resin, benzocyclobutene (BCB), and phenolic resinusing spin coating, slot coating, or the like.

Thicknesses of the second PDLs 81 b may be each set to a range betweenabout 0.1 μm and 2 μm in row directions to prevent color mixtures amongadjacent R, G, and B pixels and a range between about 0.1 μm and 1 μm incolumn directions to minimize step differences in the thicknesses of theOEMLs.

A gap between edges of the first and second PDLs 81 a and 81 b aroundthe end of the first electrode 61 may be about 1 μm.

Cracks may be formed in the first electrodes 61 and the first PDLs 81 adue to low step coverage between the ends of the first electrodes 61 andperipheral parts of via holes H. Therefore, the second PDLs 81 b areformed on the first PDLs 81 a to bury the cracks in order to improvestep coverage and prevent penetration of air and shorts betweenelectrodes.

As shown in FIG.3, the intermediate layers 63 including the OEMLs andthe second electrodes 65 are formed in openings through which firstelectrodes 61 are exposed.

The intermediate layers 63 may be formed in a single or complex stackstructure of one or more of functional layers including an emissivelayer (EML), a hole transport layer (HTL), a hole injection layer (HIL),an electron transport layer (ETL), and an electron injection layer(EIL).

The intermediate layers 63 may be formed of a low or high molecularweight organic material.

If the intermediate layers 63 are formed of the low molecular weightorganic material, the HTL and the HIL are stacked toward the firstelectrodes 61 based on the OEMLs, and the ETL and the EIL are stackedtoward the second electrodes 65 in order form the intermediate layers63. Other types of layers may be stacked in order to form theintermediate layers 63. The low molecular weight organic material may beCuPC, NPB, Alq3, or the like.

If the intermediate layers 63 are formed of the high molecular weightorganic material, the intermediate layers 63 may include only the HTLtoward the first electrodes 61 with respect to the OEMLs. The HTL may beformed of poly-(2,4)-ethylene-dihydroxy thiophene (PEDOT), polyaniline(PANI), or the like on the first electrodes 61 using ink jet printing,spin coating, or the like. Here, the high molecular weight organicmaterial may be a PPV-based or polyfluorene-based high molecular weightorganic material. Color patterns may be formed using a normal methodsuch as ink jet printing, spin coating, thermal transfer printing usinga laser, or the like, in order to form the intermediate layers 63.

The second electrodes 65 may be deposited above the whole surface of thesubstrate 10 and may be formed as common electrodes. In the OLED displayapparatus according to the present embodiment, the first electrodes 61are used as anode electrodes, and the second electrodes 65 are used ascathode electrodes. However, the present embodiments are not limitedthereto and the polarities of the first electrodes 61 and the secondelectrodes 65 may be the opposite.

If the OLED display apparatus is a bottom-emission type displayapparatus which realizes an image toward the substrate 10, the firstelectrodes 61 are transparent electrodes, and the second electrodes 65are reflective electrodes. Here, a metal having a low work function, forexample, Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Ca, LiF/Al,or a compound of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Ca,and LiF/Al, for example, may be thinly deposited to form the reflectiveelectrodes.

Although not shown in the drawings, a sealing member (not shown) and amoisture absorbent may be further formed on the second electrodes 65 toprotect the OEMLs from external moisture or oxygen.

As described above, an OLED display apparatus according to the presentembodiments includes PDLs formed of inorganic and organic insulatinglayers. Thus, non-uniformities of the thicknesses of OEMLs areminimized, and lower TFTs are planarized, thereby improving a lifespanof the OLED display apparatus.

While the present embodiments have been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present embodiments as defined by the following claims.

1. An organic light-emitting diode (OLED) display apparatus comprising:a plurality of thin film transistors (TFT) which are formed on asubstrate; a plurality of pixels comprising a planarizing layer; a firstelectrode which is formed on the planarizing layer in each pixel,wherein the planarizing layer covers the TFT; a plurality ofpixel-defining layers (PDLs) which comprise a first PDL covering an endof the first electrode and a second PDL exposing an end of the first PDLand covering the first PDL; an intermediate layer formed on the firstelectrode and comprising an emission layer (EML); and a second electrodewhich is positioned opposite to the first electrode.
 2. The OLED displayapparatus of claim 1, wherein the second PDL is formed on the first PDLto bury uneven parts of the planarizing layer.
 3. The OLED displayapparatus of claim 1, wherein the first PDL comprises inorganic layers.4. The OLED display apparatus of claim 1, wherein the first PDLcomprises at least one selected from the group consisting of SiO₂, SiNx,Al₂O₃, CuOx, Tb₄O₇, Y₂O₃, Nb₂O₅, and Pr₂O₃.
 5. The OLED displayapparatus of claim 1, wherein the first PDL is formed to a thickness offrom about 0.1 μm to about 1 μm.
 6. The OLED display apparatus of claim1, wherein the second PDL comprises organic layers.
 7. The OLED displayapparatus of claim 1, wherein the second PDL comprises at least oneselected from the group consisting of polyacryl, polyimide, polyamide(PA), benzocyclobutene (BCB), and phenolic resin.
 8. The OLED displayapparatus of claim 1, wherein the second PDL has a thickness from about0.1 μm to about 2 μm in a direction in which different color pixels arearrayed, and a thickness from about 0.1 μm to about 1 μm in a directionin which equal color pixels are arrayed.
 9. The OLED display apparatusof claim 1 wherein the planarizing layer comprises at least one of aninorganic insulating layer and an organic insulating layer.
 10. The OLEDdisplay apparatus of claim 9, wherein the planarizing layer comprises aninorganic layer comprising at least one selected from the groupconsisting of SiO₂, SiNx, SiON, Al₂O₃, TiO₂, Ta₂O₅, HfO₂, ZrO₂, BST, andPZT.
 11. The OLED display apparatus of claim 1 wherein the planarizinglayer comprises an organic layer comprising at least one of polymethylmethacrylate (PMMA), polystyrene (PS), polymeric derivative having aphenol group, acryl-based polymer, imide-based polymer, allylether-basedpolymer, amide-based polymer, fluorine-based polymer, p-xylene-basedpolymer, vinyl alcohol-based polymer.
 12. The OLED display apparatus ofclaim 1, wherein the planarizing layer has a complex stack structure ofan inorganic insulating layer and an organic insulating layer.
 13. Amethod of manufacturing an organic light-emitting diode (OLED) displayapparatus, comprising: forming first electrodes over a substrate in eachpixel; forming first PDLs covering ends of the first electrodes; formingsecond PDLs exposing ends of the first PDLs and covering the first PDLs;and forming intermediate layers comprising EMLs on the first electrodes;and forming second electrodes opposite to the first electrodes.
 14. Themethod of claim 13, wherein the second PDL is formed on the first PDL tobury uneven parts on a planarizing layer.
 15. The method of claim 13,wherein the first PDLs are formed of inorganic layers.
 16. The method ofclaim 13, wherein the first PDLs are formed of at least one selectedfrom the group consisting of SiO₂, SiNx, Al₂O₃, CuOx, Tb₄O₇, Y₂O₃,Nb₂O₅, and Pr₂O₃.
 17. The method of claim 13, wherein each of the firstPDLs is formed to a thickness from 0.1 μm to 2 μm.
 18. The method ofclaim 13, wherein the second PDLs comprise organic layers.
 19. Themethod of claim 13, wherein the second PDLs are formed of at least oneselected from the group consisting of polyacryl, polyimide, polyamide(PA), benzocyclobutene (BCB), and phenolic resin.
 20. The method ofclaim 13, wherein each of the second PDLs has a thickness from about 0.1μm to about 2 μm in a direction in which different color pixels arearrayed, and a thickness from about 0.1 μm to about 1 μm in a directionin which equal color pixels are arrayed.